If I may chip in my pennorth on this topic I would like to pick up on a
couple of things Peter has said.
First, the debateable issue of 500 years stability of microfilm. Of course
it is moot to the extent that none of us will be there in 450 year's time
to ask for our money back. Nevertheless the statement is based on the
long-standing projection for the stability of polyester base plastic used
in 'archival' microfilm. The widely quoted anticipation is that polyester
as a plastic, if stored under optimum conditions, will last for a projected
1000 years and more. Indeed, based on its first 50 years, compared with
all other film bases, it would appear to be a very safe bet and much safer
than some of the formulations used for the much more complicated
multi-laminate structure of a CD or magnetic disk.
Unfortunately what the polyester projection doesn't account for is bad
storage and its consequenences not on the polyester base, but on the much
more vulnerable gelatin emulsion. This is the part of any polyester
microfilm that is most at risk to damp, mould, finger prints etc. and,
critically, it is the part that carries the image!
My second concern is to point out that Kodak is referring to quality
standards of microfilm production and processing when they refer to
'government compliance standards', as well as any other information
transfer standards. The quality standards in terms of optical and process
quality are either not there for digital images, or so new as to have a
measure of uncertainty about their soundness in the longer term.
On the argument in general, I think that to reduce the subject to a
question of microfilm versus migration is unacceptably simplistic. Clearly
microfilm is not an answer for a multimedia application - it is only useful
for those things that are in themselves likely to be human readable and
capable of being presented meaningfully in separate frame images (i.e.
pages of text and static images - whether intended for viewing separately
or in cine motion). But where it is applicable, it is tried and tested and
very, very reliable. For complex multi-media applications a digital
solution is likely to be required for what is uniquely a digital problem.
Rational people will not put all their eggs into a single basket.
Chris Woods
Preservation Services
Dorset Archives Service
|